Bromethalin

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Bromethalin.jpg

Bromethalin is a rodenticide poison introduced in 1985 for control of vermin[1].

Bromethalin-based rodenticides are pelleted (tan or green color) grain-based products that contain 21 - 42 g of bait in paper 'place pack' envelopes[2].

The biochemical mechanism of bromethalin involves the uncoupling of oxidative phosphorylation, which is the primary means of ATP production in nervous tissues[3].

In dogs, a dose of 1.67 mg/kg is toxic, and 2.5 mg/kg (25 g of bait/kg body wt) is lethal[4].

This nonanticoagulant results in muscle fasciculations, paralysis and seizures[5].

Clinically affected dogs present with either an acute toxic episode or chronic neurological disease[6].

Chronic cases usually present 24 - 86 hours post-ingestion with vomiting, depression, ataxia, tremors, and lateral recumbency.

Diagnosis is usually based on history of exposure to the toxin, clinical signs and postmortem findings of widespread neuronal edema and vacuolation[7].

Treatment with intravenous mannitol or furosemide and activated charcoal for several days may improve the recovery rate but symptomatic and supportive care is more critical than the use of antidotal therapy[8].

References

  1. DeClementi C & Sobczak BR (2012) Common rodenticide toxicoses in small animals. Vet Clin North Am Small Anim Pract 42(2):349-360
  2. Vengeance ®, Velsicol Chemical Corp., Dallas, TX.
  3. VanLier RB & Ottosen LD (1981) Studies on the mechanism of toxicity of bromethalin, a new rodenticide. Toxicologist 1:114
  4. Merck Veterinary Manual
  5. Dorman DC et al (1991) Electroencephalographic changes associated with bromethalin toxicosis in the dog. Vet Hum Toxicol 33(1):9-11
  6. van Lier RB & Cherry LD (1988) The toxicity and mechanism of action of bromethalin: a new single-feeding rodenticide. Fundam Appl Toxicol 11(4):664-672
  7. Dorman DC et al (1990) Diagnosis of bromethalin toxicosis in the dog. J Vet Diagn Invest 2(2):123-128
  8. Dorman DC (1990) Toxicology of selected pesticides, drugs, and chemicals. Anticoagulant, cholecalciferol, and bromethalin-based rodenticides. Vet Clin North Am Small Anim Pract 20(2):339-352